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Reducing Defects Density and Enhancing Hole Extraction for Efficient Perovskite Solar Cells Enabled by π-Pb2+ Interactions.

Lirong WenYi RaoMingzhe ZhuRuitao LiJingbo ZhanLinbao ZhangLi WangMing LiShuping PangZhongmin Zhou
Published in: Angewandte Chemie (International ed. in English) (2021)
Molecular doping is an of significance approach to reduce defects density of perovskite and to improve interfacial charge extraction in perovskite solar cells. Here, we show a new strategy for chemical doping of perovskite via an organic small molecule, which features a fused tricyclic core, showing strong intermolecular π-Pb2+ interactions with under-coordinated Pb2+ in perovskite. This π-Pb2+ interactions could reduce defects density of the perovskite and suppress the nonradiative recombination, which was also confirmed by the density functional theory calculations. In addition, this doping via π-Pb2+ interactions could deepen the surface potential and downshift the work function of the doped perovskite film, facilitating the hole extraction to hole transport layer. As a result, the doped device showed high efficiency of 21.41 % with ignorable hysteresis. This strategy of fused tricyclic core-based doping provides a new perspective for the design of new organic materials to improve the device performance.
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